Here is a concrete mold that I designed and put together. The dimensions had to be rigid, and very precise to meet standards. We were short on time and these molds had to be made quickly. I cut out all of the pieces and used thread inserts, screws, and bolts for assembly. These molds are good for a limited number of castings as they degrade over time. The plywood was special form work plywood and was already prelaminated with the black coating. They can be assembled and demolded with common hand tools.